H. pylori-positive gastric tumors have also been found to have higher PD-L1 expression and T cell hypo-responsiveness, which is considered one of the carcinogenesis mechanisms by H. pylori infection.399 During GC initiation and progression, chronic EBV or H. pylori infection induces immunomodulation from a pro-inflammatory state recruiting immune cell infiltrations to an immunosuppressive microenvironment where PD-L1 is upregulated in GC cells.400. This evidence concerns the gene CD274 and gastric cancer.